Add a 'standalone_minimal' preset to build a minimal, static, OS independent, self-contained binaries of stdlib.

cmake/modules/AddSwift.cmake

@@ -131,7 +131,11 @@ function(_add_host_variant_c_compile_flags target)
 
   is_build_type_optimized("${CMAKE_BUILD_TYPE}" optimized)
   if(optimized)
-    target_compile_options(${target} PRIVATE -O2)
+    if("${CMAKE_BUILD_TYPE}" STREQUAL "MinSizeRel")
+      target_compile_options(${target} PRIVATE -Os)
+    else()
+      target_compile_options(${target} PRIVATE -O2)
+    endif()
 
     # Omit leaf frame pointers on x86 production builds (optimized, no debug
     # info, and no asserts).

cmake/modules/DarwinSDKs.cmake

@@ -26,6 +26,24 @@ if(swift_build_osx)
   configure_target_variant(OSX-R  "OS X Release"         OSX R  "Release")
 endif()
 
+is_sdk_requested(FREESTANDING swift_build_freestanding)
+if(swift_build_freestanding)
+  set(SWIFT_FREESTANDING_SDK "" CACHE STRING
+      "Which SDK to use when building the FREESTANDING stdlib")
+  set(SWIFT_FREESTANDING_TRIPLE_NAME "" CACHE STRING
+      "Which triple name (e.g. 'none-macho') to use when building the FREESTANDING stdlib")
+  set(SWIFT_FREESTANDING_ARCHS "" CACHE STRING
+      "Which architectures to build when building the FREESTANDING stdlib")
+  configure_sdk_darwin(
+      FREESTANDING "FREESTANDING" ""
+      "${SWIFT_FREESTANDING_SDK}" freestanding "${SWIFT_FREESTANDING_TRIPLE_NAME}" freestanding "${SWIFT_FREESTANDING_ARCHS}")
+  set(SWIFT_SDK_FREESTANDING_LIB_SUBDIR "freestanding")
+  configure_target_variant(FREESTANDING-DA "FREESTANDING Debug+Asserts"   FREESTANDING DA "Debug+Asserts")
+  configure_target_variant(FREESTANDING-RA "FREESTANDING Release+Asserts" FREESTANDING RA "Release+Asserts")
+  configure_target_variant(FREESTANDING-R  "FREESTANDING Release"         FREESTANDING R  "Release")
+  configure_target_variant(FREESTANDING-S  "FREESTANDING MinSizeRelease"  FREESTANDING S  "MinSizeRelease")
+endif()
+
 # Compatible cross-compile SDKS for Darwin OSes: IOS, IOS_SIMULATOR, TVOS,
 #   TVOS_SIMULATOR, WATCHOS, WATCHOS_SIMULATOR (archs hardcoded below).
 

stdlib/cmake/modules/AddSwiftStdlib.cmake

@@ -180,7 +180,11 @@ function(_add_target_variant_c_compile_flags)
 
   is_build_type_optimized("${CFLAGS_BUILD_TYPE}" optimized)
   if(optimized)
-    list(APPEND result "-O2")
+    if("${CFLAGS_BUILD_TYPE}" STREQUAL "MinSizeRel")
+      list(APPEND result "-Os")
+    else()
+      list(APPEND result "-O2")
+    endif()
 
     # Omit leaf frame pointers on x86 production builds (optimized, no debug
     # info, and no asserts).

stdlib/cmake/modules/SwiftSource.cmake

@@ -11,6 +11,21 @@ function(compute_library_subdir result_var_name sdk arch)
   endif()
 endfunction()
 
+# Return a swiftc flag (e.g. -O or -Onone) to control optimization level based
+# on the build type.
+function(swift_optimize_flag_for_build_type build_type result_var_name)
+  if("${build_type}" STREQUAL "Debug")
+    set("${result_var_name}" "-Onone" PARENT_SCOPE)
+  elseif("${build_type}" STREQUAL "RelWithDebInfo" OR
+         "${build_type}" STREQUAL "Release")
+    set("${result_var_name}" "-O" PARENT_SCOPE)
+  elseif("${build_type}" STREQUAL "MinSizeRel")
+    set("${result_var_name}" "-Osize" PARENT_SCOPE)
+  else()
+    message(FATAL_ERROR "Unknown build type: ${build_type}")
+  endif()
+endfunction()
+
 # Process the sources within the given variable, pulling out any Swift
 # sources to be compiled with 'swift' directly. This updates
 # ${sourcesvar} in place with the resulting list and ${externalvar} with the
@@ -230,12 +245,8 @@ function(_add_target_variant_swift_compile_flags
       "-F${SWIFT_SDK_${sdk}_ARCH_${arch}_PATH}/../../../Developer/Library/Frameworks")
   endif()
 
-  is_build_type_optimized("${build_type}" optimized)
-  if(optimized)
-    list(APPEND result "-O")
-  else()
-    list(APPEND result "-Onone")
-  endif()
+  swift_optimize_flag_for_build_type("${CMAKE_BUILD_TYPE}" optimize_flag)
+  list(APPEND result "${optimize_flag}")
 
   is_build_type_with_debuginfo("${build_type}" debuginfo)
   if(debuginfo)

test/CMakeLists.txt

@@ -102,6 +102,7 @@ function(get_test_dependencies SDK result_var_name)
      ("${SDK}" STREQUAL "IOS_SIMULATOR") OR
      ("${SDK}" STREQUAL "TVOS_SIMULATOR") OR
      ("${SDK}" STREQUAL "WATCHOS_SIMULATOR") OR
+     ("${SDK}" STREQUAL "FREESTANDING") OR
      ("${SDK}" STREQUAL "LINUX") OR
      ("${SDK}" STREQUAL "CYGWIN") OR
      ("${SDK}" STREQUAL "FREEBSD") OR

utils/build-presets.ini

@@ -2365,6 +2365,44 @@ mixin-preset=stdlib_DA_standalone,build
 test
 validation-test
 
+[preset: stdlib_S_standalone,build]
+mixin-preset=stdlib_base_standalone
+
+build-subdir=stdlib_S_standalone
+min-size-release
+no-assertions
+
+verbose-build
+
+[preset: stdlib_SA_standalone,build]
+mixin-preset=stdlib_base_standalone
+
+build-subdir=stdlib_SA_standalone
+min-size-release
+assertions
+
+verbose-build
+
+[preset: mixin_stdlib_minimal]
+enable-experimental-differentiable-programming=0
+enable-experimental-concurrency=0
+build-swift-dynamic-sdk-overlay=0
+build-swift-dynamic-stdlib=0
+build-swift-static-stdlib=1
+
+[preset: stdlib_S_standalone_minimal_macho_x86_64,build]
+mixin-preset=
+    stdlib_S_standalone,build
+    mixin_stdlib_minimal
+
+stdlib-deployment-targets=freestanding-x86_64
+swift-primary-variant-sdk=FREESTANDING
+swift-primary-variant-arch=x86_64
+swift-freestanding-sdk=macosx
+# For now, until clang/swiftc works correctly with "none-macho" as the OS part of target triple.
+swift-freestanding-triple-name=macosx11.0
+swift-freestanding-archs=x86_64
+
 #===----------------------------------------------------------------------===#
 # Preset for Source Compatibility Suite
 #===----------------------------------------------------------------------===#

utils/build-script-impl

@@ -224,6 +224,11 @@ KNOWN_SETTINGS=(
     sil-verify-all                                "0"               "If enabled, run the SIL verifier after each transform when building Swift files during this build process"
     stdlib-deployment-targets                     ""                "space-separated list of targets to configure the Swift standard library to be compiled or cross-compiled for"
 
+    ## FREESTANDING Stdlib Options
+    swift-freestanding-sdk                      ""                "which SDK to use when building the FREESTANDING stdlib"
+    swift-freestanding-triple-name              ""                "which triple name (e.g. 'none-macho') to use when building the FREESTANDING stdlib"
+    swift-freestanding-archs                    ""                "space-separated list of which architectures to build when building the FREESTANDING stdlib"
+
     ## Uncategorised
     install-prefix                                ""                "installation prefix"
     toolchain-prefix                              ""                "the path to the .xctoolchain directory that houses the install prefix path"
@@ -1863,6 +1868,27 @@ for host in "${ALL_HOSTS[@]}"; do
                     )
                 fi
 
+                if [ "${SWIFT_FREESTANDING_SDK}" ] ; then
+                    cmake_options=(
+                        "${cmake_options[@]}"
+                        -DSWIFT_FREESTANDING_SDK:STRING="${SWIFT_FREESTANDING_SDK}"
+                    )
+                fi
+
+                if [ "${SWIFT_FREESTANDING_TRIPLE_NAME}" ] ; then
+                    cmake_options=(
+                        "${cmake_options[@]}"
+                        -DSWIFT_FREESTANDING_TRIPLE_NAME:STRING="${SWIFT_FREESTANDING_TRIPLE_NAME}"
+                    )
+                fi
+
+                if [[ "${SWIFT_FREESTANDING_ARCHS}" ]] ; then
+                    cmake_options=(
+                        "${cmake_options[@]}"
+                        -DSWIFT_FREESTANDING_ARCHS:STRING="$(join ";" ${SWIFT_FREESTANDING_ARCHS[@]})"
+                    )
+                fi
+
                 if [[ ! "${SKIP_BUILD_LLDB}" ]] ; then
                     lldb_build_dir=$(build_directory ${host} lldb)
                     cmake_options=(

utils/build_swift/build_swift/driver_arguments.py

@@ -680,6 +680,11 @@ def create_argument_parser():
                help='build the Release variant of everything (default is '
                     '%(default)s)')
 
+        option(['--min-size-release'], store('build_variant'),
+               const='MinSizeRel',
+               help='build the MinSizeRel variant of everything (default is '
+                    '%(default)s)')
+
     # -------------------------------------------------------------------------
     in_group('Override build variant for a specific project')
 

utils/build_swift/tests/expected_options.py

@@ -412,6 +412,8 @@ class BuildScriptImplOption(_BaseOption):
     SetOption('--release', dest='build_variant', value='Release'),
     SetOption('--release-debuginfo',
               dest='build_variant', value='RelWithDebInfo'),
+    SetOption('--min-size-release',
+              dest='build_variant', value='MinSizeRel'),
     SetOption('--xcode', dest='cmake_generator', value='Xcode'),
     SetOption('-R', dest='build_variant', value='Release'),
     SetOption('-d', dest='build_variant', value='Debug'),

utils/swift_build_support/swift_build_support/targets.py

@@ -179,6 +179,12 @@ class StdlibDeploymentTarget(object):
                                          sdk_name="WATCHOS_SIMULATOR",
                                          is_simulator=True)
 
+    # A platform that's not tied to any particular OS, and it meant to be used
+    # to build the stdlib as standalone and/or statically linked.
+    Freestanding = Platform("freestanding",
+                            archs=["i386", "x86_64", "armv7", "armv7s", "armv7k",
+                                   "arm64", "arm64e"])
+
     Linux = Platform("linux", archs=[
         "x86_64",
         "i686",
@@ -207,6 +213,7 @@ class StdlibDeploymentTarget(object):
         iOS, iOSSimulator,
         AppleTV, AppleTVSimulator,
         AppleWatch, AppleWatchSimulator,
+        Freestanding,
         Linux,
         FreeBSD,
         OpenBSD,